Bismuth halide perovskite derivatives for direct X-ray detection

Metal halide hybrid perovskites containing high atomic number (Z) elements have a large absorption cross-section for high-energy X-rays, and emerge as excellent semiconductors for direct X-ray detection. Here we report a new bismuth-based perovskite derivative (DMEDA)BiI5 (DMEDA(2+): CH3NH3CH2CH2NH3CH32+) with one-dimensional crystal structure for X-ray detection. Thermogravimetric analysis shows that (DMEDA)BiI5 can withstand thermal treatment up to 287 degrees C. (DMEDA)BiI5 has a direct band gap of 1.82 eV, and a comparable X-ray attenuation coefficient to Cs2AgBiBr6 and MAPbI(3). The fabricated photoconductive X-ray detector shows a stable baseline, which indicates that (DMEDA)BiI5 has a negligible ionic migration effect. The detection sensitivity toward X-ray radiation reaches 72.5 mu C Gy(air)(-1) cm(-2).